Television apparatus



Jan 6, 1931. A. H; wATsoN 1,737,921`

TELEVISION APPARATUS Filed April 22. 1929 lllnIllllllllll/Ilffl C' i! lY Z0 /r A 1 2a f7@ y 15 and the 40 scanning `mechanism Patented Jan. 6,1931 ARTHUR H. "WATSON, F CHICAGO, ILLINOIS TELEVISION. APPARATUSanimation nica April 22,

This invention relates to improvements in television apparatus andparticularly to the scanning mechanism forming. the essential part oftheapparatus.

The present invention is an improvement over that type of apparatusdescribed and illustrated in my co-pending application for patent,Serial No. 345,005, filed March 7, 1929.

An object of the invention is to provide an improved televisionapparatus.

In the transmission and reception of television pictures today twodistinct types of pictures are formed, one consisting o a plurality ofsubstantially straight parallel lines other consisting of a plurality ofcurved parallel lines. This condition is brought about bythe employmentof apparatus in the first instance including a drum scanningmechanism,-that is, a rotating drum, from-which beams of light pass sublstantially radially to scan the object at the transmitting end and, inthe case of the re- 'ceivng' apparatus, to traverse a screen. L Such anarrangement of apparatus produces what is known as a straight linepicture.

. Other types of apparatus incor orate what isknown as thecircularscanning iscthrough or from which rays ass or are reflected in adirection substantially parallel with the axis of rotation in both thetransmittin and receiving apparatus. The result or: this arrangement isthe forming of what is known as a curved line picture.

I shall not describe in detail the construc- 3ation or operation ofthecdrum type scanner or *the* "disci type Scanner, as this mechanism iswell knownin-theart. L l

.The` principal object offmy resentinvention is to incorporate intelevision apparatus formin a part of the apparatus which is capableoproducing both straight line and curved hne pictures at will. Anotherobject is to provide televislon apparatus wherein the change fromstraight line to curved line pictures or vice versa may be accomplishedby the mere shifting of position of the scanning mechanism. Anotherobject is to provide .television apparatus which is extremely compactand 5 simple in construction.

' housing A, cluding the drum B `1929. Serial No. 356,944.

. Other objects and advantages willbe hereinafter set forthin thefollowing description and appended claims. f'

Apparatus embodying my invention is illustrated in the accompanyingdrawings forming a part of this application wherein: Fig. 1 is avertical sectional view through the apparatus;

Fig. 2 is a front elevation of the apparatus illustrated in Fig. 1;

Fig. 3 is similar to Fig. 1 illustrating the f scanning mechanism in itsshifted position to produce curved line pictures;

Fig. 4 is a schematic illustration showing the scanning mechanismadjusted for a straight line picture;

Fig. .5 is a schematic illustration similar to Fig. 1 but showing thescanning mechanism set for a curved line picture; and

Fig. 6 is a diagrammatic view illustrating the electrical circuit forcontrolling the motor and glow lamp.

In general, my improved television apparatus comprises a housing A, ascanning drum B, the construction of which has been particularly setforth in ny aforementionedpending application, a motor C for driving thedrum, a glow lamp D instantaneously responsive to the output currentfrom` a radio receiver arranged so that its light may be reilected fromthe drum B upon a translucent screenE. disposed at the front wall of thethe entire scanning mechanism ing and motor C being shiftable to eithero f the positions illustrated in Figs. 1 and 3 at will.

The housing A may be constructed of wood or metal.' and madesubstantially light-proof with itstop wall 10 forming a cover inged at11` so as to facilitate access to the interior of the housing. The glowlamp D is mounted in a tube 12 which projects fthrough an annular ring13 having a rack and pinion adjustably `associated therewith for movingthe lamp D along its optical axis toward or away from the drum B. Thisstructure permits th'e focusing of the light spot reflected from theIdrum upon the screen E. The lamp D may be any type of'lamp which iscapa le of assumin brilliancy and falling back to total dar esi inintervals of time not longer than onetwenty thousandth of a second. Forthis purpose neon gas glow lamps of the crater type have been widelyused. The light produced is highly concentrated so that it may bereproduced on the screen E in substantially the same size and shape.

The scanning drum B is rotatably mounted upon a frame 15 and gearedthrough a speed reduction mechanism enclosed in housing 16 to the motorC. In the present embodiment of the invention I contemplate using avariable speed motor, the speed of which may be controlled by theoperator by rheostat 17, the current for which may be turned on and ofl'by manipulation of a switch 18.

Both the motor C and the frame 15 upon which the scanning drum ismounted are carried upon a plate 19 which is secured by bolts and wingnuts 20 to either the bottom wall 21 or the rear wall 22 of the housingA, depending upon the nature of the picture required, i. e., straightline or curved line pictures.

The drum B has a plurality of separate concave reflectors 30 mountedthereupon, the number of which determines the number of lines in thepicture, each of which is so adjusted as to cause light reected from thelamp D to traverse the screen E in a succession of substantiallyparallel lines close enough to one another to illuminate the entirescreen when the disc is rotated at a speed of substantially 900` R. P.M. This phenomena is caused by the persistency of vision and iswellknown in television practice.

The concave reflectors 30 comprise optical elements which cause afocusing of the light from the lamp D to a spot such as represented at32 upon the screen which is virtually an image of the visiblyilluminated part of the amp.

The lamp D is controlled in general by a variable resistance 35 inseries therewith so that the operator may increase or decrease thegeneral illumination of the picture.

In operation the output terminals of a radio receiver are connected tothe input terminals 36 (see Fig. 6) of the lamp D and the alternatingcurrent so conducted to the lamp changes in proportion to the signalstrength of the broadcast picture and causes the lamp D to rise and fallin illumination, which constant change in intensity of illumination isperceived upon the screen E asthe drum B revolves at substantially 900R. P. M. or at such speed as is prescribed by the broadcasting station.It should be noted here that the speed and relative position of the drumB must exactly coincide with the similar rotat- ,ing part of thescanning mechanism at the broadcast station. Hence the rheostat 17.

Assuming that the apparatus is assembled as shown in Fig. 1, and withreference to Fig. 4, it will be seen that the light reflected from lampD will be reflected from the reflectors 30 along Substantially radialpaths with respect to the axis of the drum,-hence the line drawn by themoving spot 32 will be a straight line and as the drum continues torevolve a plurality of straight lines will be so formed to comprise acomplete picture, the persistency of vision operating to maintain thepicture wholly upon the screen for one revolution of the drum. Upon thenext revolution a new picture will be formed.

It is important that the scanning apparatus embodying my invention shallbe constructed with the concave reflectors 30 set at substantially 45degrees from the axis of rotation as otherwise a shift from straightline to curved line pictures would be difficult to accomplish.

Let us assume now that it is desirous to produce a curve line picturebecause the broadcasting station in operation at this time isbroadcasting with apparatus including a disc type scanner. The operatorthen will shift the plate 19 bearing the motor and scanning drum to theposition shown in Fig. 3 and schematically in Fig. 5, at the same timethrowing the reversing switch 40 on motor C. The result of this changein assembly will cause light reflected from the lamp D to be projectedaway from the reflectors 30 on the rum along axes which aresubstantially concentric with the axis of rotation and a curved linewill be produced as the spot 32 traverses screen E.

What I claim is new and desire to secure by Letters Patent of the UnitedStates is:

l. Television apparatus comprising a source of concentrating light, ascreen, a rotatable drum and a plurality of focusing re'- flectors, saidreflectors being so arranged as to reflect and focus said concentratedlight upon the screen along axes substantially radial to the axis of thedrum when the axis of the direct light beams from said light areperpendicular to the vplane of rotation of the drum, whereby a linedescribed by the focused light upon the screen when said drum is rotatedis substantially straight.

2. Television apparatus comprising a source of concentrated light, ascreen, a rotatable drum and a plurality of focusing reflectors carriedon said drum, said reflectors being arranged circumferentially about thedrum and having their reflecting surfaces inclined at substantially 45degrees from the axes of the drum, said light source having its opticalaxis perpendicular to an axis perpendicularly intersecting the center ofsaid screen, both ofsaid axes intersecting in the lane of saidreflectors, each of said reflectors ginning with Vone certain reflectorhaving its angle of inclination slightly less than the next adjacent andsucceedmg reflector thereby causing the successively described lines'upon the screen to lie one beneath the other.

mamar 3. In a television apparatus, a rotatable member, a plurality ofreflectinig surfaces on said member angularly disposed with respect tothe axis of rotation thereof, a fixed source of light, a fixed viewingscreen and means permitting the shifting of the axis of rotation of saidrotatable member to vary the path of light from said light source as itis relected from said surfaces to said screen to scan in straight orcurved lines at will.

4. 1n a television apparatus, a. rotatable member, a plurality ofreflecting surfaces on said member angularly disposed` with respect tothe axis of rotation thereof, a source of 1i ht, a viewing screen andmeans for permitting relative movement between said li ht source and theaxis of said rotatable mem r to Vary the path of light from said lightsource as it is reiected from said surfaces to said screen to scan instraight or curved lines at will.

In witness whereof, l hereunto subscribe my name this 19 day of April,1929.

. ARTHUR H. WATSON.

